| Little Bear Adventures Ltd | Administrative & support | 2022 |
| Little Bear Transport Limited | Wholesale & retail | 2014 |
| Little Bears Pre-School | Education | 2011 |
| Little Faringdon Water and Drainage Management Company Limited | Water & waste | 2026 |
| Little Swim Company LLP | | 2015 |
| Littleton Farm Management Limited | Real estate | 2008 |
| LIV Industries Limited | Other services | 2025 |
| Living Jewels Limited | Information & communication | 2004 |
| LK HR Services Ltd | Administrative & support | 2020 |
| Lodo Holdings Ltd | Households | 2023 |
| Logistics Support Ltd | Transport & logistics | 2014 |
| London Plains Limited | Manufacturing | 2016 |
| Longcroft Developments Limited | Real estate | 2022 |
| LOU Prior Consulting Ltd | Professional & scientific | 2024 |
| LOW Frequency Solutions Limited | Professional & scientific | 2011 |
| LTM Property Services Ltd | Real estate | 2020 |
| Lucinda Fredericks Equestrian Ltd | Agriculture & fishing | 2013 |
| Lucky 66 Ltd | Hospitality | 2018 |
| Lucky Dave Limited | Professional & scientific | 2012 |
| Lucy's Hair Boutique (Devizes) Limited | Other services | 2016 |
| Luke Fernandez Mortgages Limited | Financial services | 2021 |
| Luminar Consulting Limited | Professional & scientific | 2009 |
| LUX Group Holdings Ltd | Manufacturing | 2018 |
| Lynchmere Limited | Extraterritorial | 2021 |
| Lynchmere Rezizt Limited | Manufacturing | 2019 |
| Lyons Homes Limited | Real estate | 2017 |
| M & D Crest Consultants Ltd | Administrative & support | 2024 |
| M Godding Ltd | Wholesale & retail | 2006 |
| M Harris Avionics Ltd | Professional & scientific | 2017 |
| M&L Arms Limited | Hospitality | 2016 |
| M&L Collins Limited | Hospitality | 2025 |
| M. E. Agri Ltd | Agriculture & fishing | 2015 |
| M.B.Joinery (Chirton) Limited | Manufacturing | 2002 |
| M.G. Leisure Limited | Arts & recreation | 2000 |
| Mac's Theatre School Limited | Arts & recreation | 2017 |
| Macdonald Technology Consultants Limited | Information & communication | 2023 |
| Mackemsley Business Consulting Ltd | Professional & scientific | 2018 |
| Macpherson Technology Associates Ltd | Professional & scientific | 2001 |
| Madanu Ltd | Other services | 2015 |
| Majc Limited | Construction | 2008 |
| Major Dairy Farming Ltd | Agriculture & fishing | 2022 |
| Majordevs Limited | Information & communication | 2025 |
| Make Money Go Further Limited | Financial services | 2010 |
| Manor Farmyard (Urchfont) Management Company Limited | Real estate | 2014 |
| Manor IT Services Limited | Information & communication | 2023 |
| March Twenty Spare One Ltd | Extraterritorial | 2020 |
| March Twenty Spare Two Ltd | Extraterritorial | 2020 |
| Marden Associates Ltd | Professional & scientific | 2025 |
| Marform Limited | Professional & scientific | 2002 |
| Marinesar Ltd | Manufacturing | 2018 |
| Mark Graham Limited | Professional & scientific | 2011 |
| Market Lavington (White Horse) Management Limited | Households | 2001 |
| Market Place Flooring Limited | Construction | 2018 |
| Market Town Memorials Ltd | Manufacturing | 2019 |
| Marque IV Limited | Manufacturing | 2003 |
| Marquis Partnership Limited | Transport & logistics | 2024 |
| Marsden's Lettings & Management Services Limited | Real estate | 2012 |
| Marshall Drilling Ltd | Construction | 2016 |
| Marshall Property Holdings SW Limited | Financial services | 2024 |
| Martin Barnes Creative Limited | Administrative & support | 2024 |
| Mason Elias Properties Ltd | Real estate | 2019 |
| Mason Science Limited | Administrative & support | 2004 |
| Massey Specialist Welding Limited | Manufacturing | 2022 |
| Massmedia Limited | Information & communication | 1996 |
| Masters Mechanical Limited | Wholesale & retail | 2023 |
| Matmax Estates Ltd | Real estate | 2026 |
| Matt Hill Expeditions Ltd | Arts & recreation | 2020 |
| Matt Walsh Physiotherapy Limited | Health & social care | 2013 |
| MAX Corporate Services Ltd | Administrative & support | 2010 |
| MAX Limited | Financial services | 1909 |
| Mayella Limited | Information & communication | 2017 |
| MBC Hospitality Group Ltd | Hospitality | 2025 |
| MC Analytics Consultancy Ltd | Information & communication | 2023 |
| Mcballester Ltd | Construction | 2012 |
| Mccormick & Mccormick Limited | Professional & scientific | 2015 |
| MCG Site Services Limited | Manufacturing | 2015 |
| MDC Geoconsulting Limited | Professional & scientific | 2025 |
| MDH Financial Services Limited | Financial services | 2014 |
| Mechbridge Limited | Wholesale & retail | 2025 |
| Melksham Kitchen & Appliance Centre Ltd | Wholesale & retail | 2009 |
| Melmic Ltd | Professional & scientific | 2007 |
| Menopause Better App Ltd | Other services | 2025 |
| Mental Pictures Limited | Arts & recreation | 1990 |
| Merison Sporting Limited | Arts & recreation | 2012 |
| Merlin Health & Safety Limited | Professional & scientific | 2010 |
| Merryn Ltd | Professional & scientific | 2024 |
| Metabolics Ltd. | Wholesale & retail | 1993 |
| Mevja Ltd | Professional & scientific | 2023 |
| Midwife & ME Workshop Ltd | Education | 2021 |
| Mike Garbutt Transport Limited | Transport & logistics | 2000 |
| Mikey's Barber Shop Limited | Other services | 2010 |
| Miles Johnston Media MJM Ltd | Information & communication | 2011 |
| Mill Farm Glamping Limited | Arts & recreation | 2012 |
| Mill Services Ltd | Professional & scientific | 2013 |
| Milsom Court Management Company Limited | Real estate | 2007 |
| Mindsetlxd Ltd | Professional & scientific | 2026 |
| Minehead Health and Wellbeing CIC | Health & social care | 2024 |
| Mipo Coffee Shop Ltd | Wholesale & retail | 2008 |
| Mitch Griffiths Limited | Arts & recreation | 2011 |
| Miteq Group Limited | Financial services | 2025 |